Explosive train arming device



Nov. 27, 1962 Filed De c. 15, 1955 D. A. PLANK EXPLOSIVE TRAIN ARMINGDEVICE 2 Sheets-Sheet 1 INVENTOR DICK A. PLANK ATTORNEY Nov. 27, 1962 D.A. PLANK 3,065,694

EXPLOSIVE TRAIN ARMING DEVICE Filed Dec. 13, 1955 2 Sheets-Sheet 2 FICA.

INVENTOR DICK A. PLANK BY ATTORN YJ' United States latent Gfificeassess-4f Patented Nov. 27, 1%62 The invention described herein may bemanufactured and used by or for the Government of the United States ofAmerica for governmental purposes without the payment of any royaltiesthereon or therefor.

This invention relates to arming devices for ordnance explosive trainsand more particularly to an arming system wherein a means is providedfor changing the medium separating the various vital components of aprimer-detonatorabooster system in order to accomplish the armingoperation.

At the present time, primer-detonator-booster trains in underwaterordnance utilize the principle of adequate physical separation of theVarious components in air to prevent ultimate detonation of the booster.Components so separated are in a safe condition since shock caused bythe detonator is attenuated by traveling through air with the resultthat it is too weak to cause initiation of the booster charge. To armsuch a system, mechanism must be provided to mechanically move thedetonator into the critical range where complete detonation will bepossible upon firing actuation of the mine or other ordnance device.This arrangement, by its very nature, results in relatively complexmechanical devices inherently subject to malfunctioning,

damage, or improper adjustment. There are indications that certainfailures in underwater ordnance are attributable to faulty extenderfunctioning. In order to function properly these complex extendermechanisms must of necessity be in perfect working order. This isdifficult to insure in view of the fact that such mechanisms aresusceptible to damage from handling and from launching shock.Furthermore, the mechanism components are susceptible to a certainamount of deterioration in storage and this contributes to thepossibility of malfunctioning. Also many detonator extender mechanismsused in underwater ordnance are dependent upon water pressure for theiroperation. This presents serious operational limitations when use inshallow waters is required. The uncertainty of operation coupled withthe hazard of accidental arming by improper final assembly leavesmuch'to be desired in the arming systems now in use.

In general the present invention utilizes the principle that shock wavesare conducted more efficiently by a liquid medium such as water than bya gas medium such as air. In employing this principle of difference ofeiiiciency in the transmission of energy the present invention providesfor a fixed distance of separation between the donor charge (detonator)and the acceptor charge (booster). This distance is so designed as toprevent detonation of the booster when the separating medium is air orother gaseous material. However, in this invention, there is providedmeans whereby the air separating these two vital components of theexplosive train may be displaced by a liquid medium such as water. Oncethis is accomplished the explosive train is positively armed due to theability of the liquid medium to permit propogation of the detonatingenergies with suflicient force to activate the acceptor charge. Means isalso provided to reverse the above procedure whereby the arming liquidmedium may be drained from the space separating the donor and acceptorcharges in which event the explosive train is again rendered safe. Thetime involved in changing the medium separating the components may becontrolled, as will later be more fully described,

so that positive arming of the ordnance device can be appropriatelydelayed to insure safety of the launching vessel. Furthermore it will beapparent that the mere presence of water in sufficient quantity to fillthe detonator chamber will cause arming regardless of the depth of thewater in which the ordnance device is placed.

The simple exchange of water for air within the detonator chambereliminates the necessity of complicated detonator extender mechanismsand provides an arming system which is both reliable and safe.

An object of the present invention is the provision of an arming systemin which the changing of the character of the separating medium betweenthe various vital components of an explosive train will change it from asafe to an armed condition.

Another object is to provide an explosive train arming mechanism inwhich the arming function is completely independent of the water depthof submersion of the parent mine or other underwater ordnance device.

A further object of the invention is the provision of an arming devicewhich eifects the sterilization of a mine or other ordnance by the meredraining oif of the liquid medium separating the components of itsexplosive train.

Still another object is to provide a new and improved means for armingan ordnance explosive train in which there is adequate time delay incompleting the arming operation to insure safety to the launchingvessel.

A still further object of the invention is to provide an arming devicewhich is sufficiently rugged to prevent damage during handling orlaunching and which may not be accidentally armed by improper assembly.

Still other objects and advantages will be apparent from the followingdescription taken in connection with the accompanying drawings, inwhich:

FIG. 1 is a sectional view of an arming system constructed in accordancewith my invention;

FIG. 2 is a sectional view of a modification of the inventionillustrating a system in which the arming liquid is contained whollywithin the system;

FIG. 3 is a sectional view of a floating moored mine incorporating amodification of the invention;

FIG. 4 is a fragmentary sectional view showing a modification of theinvention as applied to projectiletype ordnance, the arming mechanismbeing in the safe position; and

FIG. 5 is a fragmentary sectional view similar to FIG. 4 showing thedevice in the armed position.

Referring now to the drawings wherein like reference charactersdesignate like or corresponding parts throughout the several views,there is shown in FIG. 1 a portion of a mine or other ordnance weaponhaving a casing 10 which houses a main charge 11. The periphery ofcasing 16 has an opening therein to permit the insertion of adetonator-booster housing 12. to a position where it will be surroundedby the main charge. Housing 12 may be of any appropriate configurationbut for the purpose of illustration the housing is shown as having acylindrical hollow center portion 13 having an outwardly extendingannular flange 14 which in turn has a stepped outwardly extendingannular flange 15 projecting therefrom. Flange 15 may be bolted orsecured in any appropriate manner to a recess presented by an inwardlyextending annular flange 16 formed in the casing 16.

The housing 12 has a base plate 17 in which is located a centrallydisposed opening 18 surrounded by an internally threaded boss 19 locatedon the inner face of the base plate. Boss 19 is adapted to receive anexternally threaded connector member 20 to which is secured thedetonator component 21 of the explosive train. Where appropriateconnector 20 will also contain a sensitive primer element to actuate thedetonator. Thus the detonator is secured within the interior of thehousing 12 in a position substantially coaxial with the housing.Appropriate electrical leads 22 connect the detonator or theintermediate primer when used, with the usual firing mechanism such, forexample, as the firing mechanism 69 of FIG. 3. This causes electricaldetonation of the detonator when the firing mechanism is actuated. Thelead wires are separated from the main charge 11 by means of anappropriate conduit such as the hollow tubing 23 secured to the lowerface of base plate 17.

In accordance with the principle of the present invention a boostercharge 24 is fixed in spaced relation with the primer-detonatorcomponent 21. In the embodiment shown in FIG. 1 of the drawings thebooster is of a hollow cylindrical shape and is so located as to besubstantially coaxial with the detonator and having its inner surface inspaced relation thereto at a distance predetermined in accordance withthe composition of both the detonator and booster charges. The boostercharge 24 is housed in a container 25 adapted to fit the interior of thedetonator-booster housing 12 and having inner and outer cylindricalwalls 26 and 27 connected by a transverse portion 23. The outer face ofconnecting plate 28 is provided with a plurality of protuberances 28' soas to space the booster container from the base plate 17 of the housingin order to permit flow of liquid between the two plates as willhereinafter be more fully described. The diameter of the inner face ofwall 26 is slightly greater than that of boss 19 to also permit flow ofliquid between these two members.

As will be seen in FIG. 1 the inner wall 26 forms in 'eifect a detonatorchamber designated as 29. Inner wall 26 extends longitudinally outward agreater distance than does outer wall 27 and at its outermost end isinternally threaded. The outer portion of the detonator chamber iscovered by a circular orifice plate 30 which rests on an abutmentshoulder 31 formed on the inner surface of wall 26. Adjacent orificeplate 30 lies a circular soluble disc 32 held in place by an externallythreaded circular cap member 33. Cap 33 may be constructed of plastic orother suitable material and contains a plurality of orifices 34. Theseorifices and the orifices 35 located in plate 30 are so designed as topermit a predetermined rate of flow of liquid from the exterior of thecasing 10 to the interior of the detonator chamber 29. Variousarrangements could be made to insure against premature entrance ofliquid into the detonator chamber during storage and handling. Forexample a water impervious cap could be placed over the end ofcylindrical wall 27 and removed when the ordnance is ready for use. Alsoa protective impervious disc could be placed between cap 33 and thesoluble disc until ready for use and removed prior to launching.

Referring to FIG. 1 it will be seen that booster container 25 isretained within the housing 12 by means of a cover plate 36. This plateis provided with a central aperture 37 through which extends thecylindrical center portion of the booster container. The cover plate issecured in place by means of bolts 38 or the like which threadinglyengage annular flange 14 of the detonatorbooster housing 12.

In order to permit proper drainage of water from the detonator chamberupon recovery of the ordnance device from the water and to also permitflooding of the detonator chamber should the openings provided in cap 33be buried in the mud, the present system includes at least two auxiliaryvents. These vents connect the detonator chamber with the exterior ofcasing 10 through openings 39 positioned at approximately 120 on eitherside of the cap 33 and in this manner the casing is provided withindependent venting means disbursed about the periphery thereof.

In construction, the auxiliary vents comprise a conducting pipe tisecured in any suitable manner to the detonator-booster housing 12 and aboss 42 secured to the inner face of the casing. Cavity 41 formed withthe boss contains liquid flow control elements similar to those locatedin the outer portion of the detonator chamber. These elements consist ofan orifice plate 43, a soluble disc 44 and an externally threaded cap 45having a plurality of orifices located therethrough.

An explosive train incorporating the present invention remains in aninert or safe condition during storage and handling due to the fact thata selected gaseous substance such as air initially fills the detonatorchamber thereby separating the detonator 21 from the booster charge 24.The size of this air gap and the thickness of Wall 26 are so designed inaccordance with specific explosive compounds to be used that should thedetonator be prematurely activated the booster charge will not be setoff due to the poor shock transmitting characteristic of air.

When the ordnance device is launched into a body of Water the orificeslocated in cap 33 will permit the entrance of water to the soluble disc.In time the disc will dissolve permitting entrance of Water into thedetonator chamber 29 by way of the orifices in plate 36 Due to the factthat fluids can transmit higher detonating energies for given distancesthan can gaseous material, shock waves created by the explosion of thedetonator will be transmitted in sufficient force to cause the explosionof the booster charge which in turn activates the main charge toaccomplish complete explosion of the ordnance device.

In FIG. 2 there is shown a modified embodiment of. the invention whereinthe mine or other ordnance device is provided with an appropriate liquidreservoir and pumping system which will effect the mechanical change ofshock transmitting medium located in the detonator chamber. In thisembodiment the booster container 46 is surrounded by the main charge 47and appropriately retained by means of a cover plate 48 secured to amine casing 49 by bolts 50 or other appropriate fastening means. Plate48 has secured through an opening therein a threaded coupling 51 whichretains the primer-detonator element 52 in a central positionsubstantially coaxial with the cylindrical detonator chamber 53 formedby the inner wall 54 of the booster container. Lead wires 55 connect theprimer-detonator with a conventional electrical firing mechanism meanssuch as the firing mechanism 59, FIG. 3. A booster charge 56 iscontained between the coaxial inner and outer walls of the boostercontainer.

The base of the booster container is provided with a pair of openings incommunication with chamber 53 to which are respectively secured conduits57 and 58. In a normal position of a moored mine, conduit 57 connectsthe upper portion of chamber 53 with the upper portion of a reservoir 59which contains a copious supply of liquid medium such as light oil orwater and conduit 58 completes a fiuid connection between the lower partof chamber 53 by way of a pump to the lower portion of reservoir 59. Aconduit 69 leads from the lower portion of reservoir 59 and connectswith conduit 58 through a conventional two-way pump shown schematicallyat 61.

A clock device 61a or other appropriate means can be utilized toactivate pump 61 whereby liquid from reservoir 59 can be forced into thedetonator chamber causing the gaseous or air medium originally containedtherein to be evacuated through conduit 57. Thus with the liquid mediumfilling the space in chamber 53 between detonator 52 and the boostercharge 56 the explosive train is in an armed condition. While a simpleflow circulation system has been shown for the purpose of illustrationother conventional systems employing liquid-air discriminating valvesand the like may be used.

This form of the invention has the advantage of permitting mechanicalsterilization of the explosive train. To achieve this result a clockdevice 61a or other means aoeaee t may be utilized to actuate pump 61 ina reverse direction whereby the liquid medium will be exhausted from thedetonator chamber 53 and the explosive train thus rendered in a safe orunarmed condition.

On FIG. 3 of the drawings is shown the principle involved in the presentinvention as applied to a moored mine. For purposes of illustration Ihave shown the mine as comprising a spherical casing 62 having extendingtherefrom a plurality of firing horns 63 for actuation of the mine uponimpact. The mine casing has an appropriate mooring fixture 64 to enablethe mine to be held at a predetermined position below the surface of thewater by a mooring cable (not shown) affixed thereto. The interior ofthe mine comprises a main charge 65, a main booster charge 66 andinitiating booster 67, a primer-detonator element 68 and a conventionalfiring mechanism 69. The detonator-booster housing 76 is located in theupper portion of the mine and secured to the casing thereof by bolts 71or other appropriate fastening means. In to this housing is placed theinitiating booster container 72 which is held in place by a retainingplate 73 which in turn is bolted to the housing. The inner cylindricalwall 74 forms a detonator chamber 75 which is defined at its outer endby an orifice plate 76 having openings therein. A soluble disc 77 and athreaded retaining cap 78 having openings therein are located outwardlyof the orifice plate.

Detonator 68 is secured to the base plate 7% of the booster-detonatorhousing by means of a threaded coupling 39 which also connects thedetonator and appropriate feed wires 81 which in turn connects with thefiring mechanism 69. Firing mechanism 69 is connected to each of thefiring horns 63 as shown.

An important feature of this modification is the inclu sion of aplurality of detonator chamber vents which connect the chamber 75 withthe exterior of the mine casing. Base plate 79 is provided with anopening 82 therethrough for each of such vents. An appropriate tubing 83extends through each opening from the detonating chamber 75 to a ventopening provided in the surface of the mine casing. As shown in FIG. 3each vent opening has associated therewith an appropriate soluble disc84 located between an orifice plate 85 and a cap member 86 also havingorifices therein.

In operation this modification of the invention is armed in a mannersimilar to that described in connection with FIG. 1 of the drawings.When the mine is immersed in water the liquid enters through theapertures in retaining cap 78 and also in the various cap members 86covering the vents. In due time the presence of the water attacks thesoluble Washers which when dissolved permit the entry of water into thedetonator chamber Thus with this medium having high efficiency fortransmission of shock energy the initiating booster charge 67 will bedetonated upon explosion of the detonator member 68. A distinctadvantage of the use of my invention in the moored type of mine lies inthe fact that the mine is rendered safe once it breaks free from itsmooring and becomes free floating as shown in FIG. 3. As will be seenfrom FIG. 3, in the free-floating condition of the mine the detonatorchamber rides above the normal water line and thus through the use ofvents as shown the chamber is automatically drained of water. Thispositively disarms the mine. This arrangement is decidely advantageousover the present type of disarming device, namely the extendermechanism, since the latter is readily corroded when exposed to seawater for an extended period and cannot always be relied upon tofunction properly.

FIG. 4 of the drawings illustrates the application of the invention torocket or gun-projectile type ordnance. The device as shown in FIG. 4 isin the safe position and is adapted to a projectile having a body 87which carries a nose assembly 83 in which is located a conventional typenose fuze (not shown). The forward portion of body 87 is internallythreaded at 89 to receive a booster detonator housing generallyindicated at 90. This housing is so positioned as to permit'the maincharge 91 of the projectile to substantially surround the housing. Theforward portion of housing is bifurcated having an inner cylindricalwall 92 and an outer cylindrical Wall 93. These walls define an annularrecess 94 which serves as a container for booster charge 95. Theinterior of housing 90 comprises an elongated chamber 96 closed at oneend by the end Wall 97 and at its opposite end by an externally threadedcap 98. This cap has a threaded central aperture 99 adapted to receivean externally threaded primer-detonator coupler 100. The coupler hasextending from the forward face thereof a conventional primer device 101which may be actuated when struck by a firing pin MP2 or the like of thefuze mechanism. A detonator 103 extends rearwardly of coupler wt) and ispositioned coaxially with chamber 96.

As seen in FIG. 4 a piston-like sliding safety block 104 is locatedWithin chamber 96 and in the safe position is adapted to surrounddetonator 103 thus effectively separating the detonator and the boostercharge by a mass of shock absorbing material. Block 104 is preferablymade of soft steel or other material having poor shock transmittingcharacteristic. The rear face of the block is formed with a circularrecess 105 within which is secured a spring 106 for normally maintainingthe block 104 in the safe position. In response to a sustainedacceleration of a predetermined magnitude, a rearward movement will beimparted to block 104 whereupon the liquid disposed in the after chamberwill be transmitted through apertures 167 into the forward or armingchamber. The size and number of the apertures may be so designed as topermit the exchange of the liquid medium for the solid medium within thetime limitations of sustained acceleration. Once the sliding safetyblock has been moved and retained in the after chamber the liquid mediumcompletely surrounds the detonator thus arming the explosive train, asshown in FIG. 5. The time factor required in the arming cycle willprevent premature arming of the train due to accidental dropping of theround. Obviously the time of deceleration caused in dropping would betoo short an interval to allow any appreciable quantity of liquid to betransferred. Also the same safety advantage would apply if the roundstruck an object such as the edge of a barricade or limb of anover-hanging tree which might be too close to the launcher or gun.Furthermore once the safety block has been fully retracted the snap ringdevice 108 engages the forward collar of an annular groove 109 formed inhousing 90 which prevents the block from later returning and disarmingthe train. This is an improvement over the use of the rotating principlefor arming gun projectiles since the latter begin to fail at extremeranges or when the gun rifling begins to appreciably wear and fails togive the round a sufiiciently high rate of initial rotation.

From the foregoing description it is apparent that a means has beenprovided whereby the shock transmitting medium which exists between thevarious vital components of a primer-detonattor-booster system may bechanged in character to arm or disarm an ordnance device without thenecessity of providing a mechanical means for bringing the componentscloser together for this purpose. This simple and positive armingoperation utilizes the fact that different materials have differentdegrees of effectiveness in transmitting shock wave energies from adetonator to a booster charge spaced therefrom. Thus the simple exchangeof shock transmitting medium obviates difficulties presented by complexmechanical extended mechanisms, simplifies the design of certain typesof underwater 0rdnance, and insures positive arming of an explosivetrain irrespective of the depth of water in which the ordnance device islaunched,

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is, therefore, to beunderstood that within 7 the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed a new and desired to be secured by Letters Patent of theUnited States is:

1. In an explosive train arming means the combination of a body member,said body having a chamber therein, a donor charge supported in saidchamber in spaced relation to the sides thereof, an acceptor chargesurrounding said chamber in part, said donor charge and acceptor chargebeing so spaced as to render shock waves caused by explosion of saiddonor charge ineffective to cause explosion of said acceptor charge whenthe chamber is filled with air, and means for introducing a liquid intosaid chamber to increase the shock transmission to the acceptor chargeupon explosition of the donor charge.

2. In an explosive train the combination of a body member, a detonator,means for exploding said detonator, a booster charge spaced from saiddetonator, said body member having a chamber therein within which saiddetonator and said booster charge are disposed, said chamber beingnormally substantially filled with a medium characterized bysufiiciently poor shock-transmitting quality to prevent ignition of saidbooster charge by the explosion of the detonator, and means forreplacing said medium with a second medium having a bettershocktransmission characteristic whereby shock waves caused by explosionof said detonator will explode the booster charge.

3. The invention as set forth in claim 2, wherein the first said mediumis a gaseous substance.

4. The invention as set forth in claim 2 wherein said second medium is aliquid.

5. The invention as set forth in claim 2 wherein the first said mediumis a gaseous substance and said second medium is a liquid,

6. In an explosive train the combination of a body member, a detonator,means for exploding said detonator, a booster charge spaced from saiddetonator, said body iiiember' having a chamber therein within whichsaid detonator and said booster charge are disposed, said chamber beingnormally substantially filled with a medium characterized by poorshock-transmitting quality, means connecting said chamber with a liquidsupply and means for introducing said liquid into said chamber toincrease shock-transmission to the booster charge upon explosion of thedetonator.

7. The invention as set forth in claim 6 wherein said means forintroducing liquid comprises an apertured plate initially sealed by asoluble disc.

8. The invention as set forth in claim 6 wherein said means forintroducing said liquid includes a pump and means for actuating saidpump.

9. The invention as set forth in claim 6 wherein the first said mediumconsists of a sliding block adapted to be moved from an initial positionbetween said detonator and booster, said block having apertures thereinfor introducing liquid into said chamber upon movement of the block.

10. In an explosive train arming means for use in an underwater ordnancedevice the combination of a casing having a main charge therein, abooster charge in proximity with said main charge, a detonator in spacedrelation with said booster charge, said space between the detonator andbooster charge comprising a chamber adapted to be filled with a gaseoussubstance in the unarmed condition of the explosive train, said casinghaving an opening therein connecting said chamber with the exterior ofthe ordnance device, a soluble disc arranged transverse of said opening,apertured retaining means for said disc, said disc being adapted todissolve upon immersion in water to permit entry of Water into saidchamber, and means for actuating said detonator.

11. The invention as set forth in claim 10 wherein said 8 casing isprovided with BUXlllZll'Y means for connecting said chamber with theexterior of the casing, said auxiliary connecting means having a solubledisc therein adapted to dissolve when submerged in water.

12. An ordnance explosive train comprising a booster charge, a detonatorin spaced relation with said booster charge, the space between thedetonator and booster charge comprising a chamber adapted to be filledwith a gaseous substance in the unarmed condition of the explosivetrain, a liquid reservoir, conduit means connecting said chamber withsaid reservoir, a pump located in said conduit means and adapted totransfer liquid from said reservoir to said chamber, and means foractuating said detonator.

13. The invention as set forth in claim 12 wherein said pump isreversible to withdraw liquid from said chamber thereby to disarm theexplosive train.

14. In an explosive train arming means for use in an underwater ordnancedevice, the combination of a casing having a mean charge therein, abooster charge in proximity with said main charge, a detonator in spacedrelation with said booster charge, the space between the detonator andbooster charge comprising a chamber adapted to be filled with a gaseoussubstance in the unarmed condition of the explosive train, said casinghaving an opening therein connecting said chamber with the exterior ofthe ordnance device, a soluble disc arranged transverse of said opening,apertured retaining means for said disc, said disc being adapted todissolve upon immersion in water to permit entry of water into saidchamber, means for actuating said detonator, drain means connecting saidchamber with the exterior of said casing, said drain means being locatedbelow the plane of said chamber, and a soluble disc located in saiddrain means.

15. In an explosive train arming device for projectiles, the combinationof a casing, a booster charge within said casing, a detonator in spacedrelation to said booster charge, the space between the detonator andbooster charge comprising the forward portion of a chamber, said chamberextending rearwardly of the detonator and booster charge, a slidablepiston within said chamber, said piston being composed of a materialhaving poor shocktransmission characteristic, spring means for normallyholding said piston in the forward portion of said chamber intermediatesaid detonator and booster charge, a quantity of liquid located in therearward portion of said chamber, said piston having longitudinalapertures therein to permit said liquid to flow to the forward portionof said chamber upon rearward movement of said piston, means for lockingsaid piston in its rearward position, and means for actuating saiddetonator.

16. An explosive train arming means comprising a body member having adonor charge and an acceptor charge therein, said charges being inspaced relation to one another, a separating medium located in the spacebetween said charges, said medium being a substance having a poorshock-transmission characteristic, and means for replacing said mediumwith a liquid medium having better shock-transmission characteristic.

17. An explosive train arming means comprising a body member having adonor charge and an acceptor charge therein, said charges being inspaced relation to one another, a gaseous medium having a poorshocktransmission characteristic located in the space between saidcharges, and means for replacing said gaseous medium with a liquidmedium having better shock-transmission characteristic.

References (listed in the file of this patent UNITED STATES PATENTS1,751,616 Brayton Mar. 25, 1930

